Overloading Operator

I have a Matrix class and I am trying to overload the multiplication sign.
It compiles without error and runs, however it does not display the matrix like it should. So I want to make sure the error is not in my overload operation.

It still is not displaying in the textbox. I want to note that I have 2 other textboxes that are showing output of matrices using the display function I've created. I've corrected my algorithm to the following:

I finally found some code from 3 years ago. I am in fact still "working" on this MatrixCalculator project.:icon_cheesygrin:
I did an override of the ToString method, the variables starting with an underscore a private fields of the class. Give it a try, don't knoow if it will change anything.

This is my first program in C#, I've coded in C++ and Java, which makes it an easy transition. However, I'm still getting used to the C# way. Do I put the overloaded toString method in my matrix class, or as a function in the form?